As a research scientist of my aquaintance said to me, 'You want a grant nowadays you have to mention Global**** Warming and carbon reducing posibilities of your work'. As he does military enginnering it is a bit difficult. the latest thing being punted is air conditioning, about twenty years ago HFC's were brought in to DA_DAAAAAAAA Stop making holes in the Ozone layer, and that can lead to increased cancer rates. Now OH Dear it is two thousand times worse than CO2 as a green house gas. So lets replace it with a more friendly coolant we'll use DA_DAAAAAAAAA CO2. You really can't make it up. At least most military vehicles, the air conditioning is the gap in the doors and roof. According to the BBC 'Costing the Earth' if you need to recharge the air conditioning on your low emission super tin box, then the amount of coolant lost is the same global warming efect as driving ten thousand miles. So there you go lads! Why should we feel guilty?